George Clooney stumped David Letterman during his final appearance on The Late Show on Thursday by handcuffing himself to the outgoing late-night TV host and throwing away the key.

A night after his pal Julia Roberts made her final appearance on the show, which Letterman will leave next week, Clooney tried to talk the TV personality out of retirement.

Refusing to chat about his September wedding and his marriage to lawyer Amal, Clooney asked, "What are you doing?" before slapping the handcuffs on Letterman's wrist and announcing, "You're not going anywhere, David Letterman".

The impromptu stunt prompted Letterman to joke, "Now, George, is this (the handcuffs) something left over from the bachelor days?"

Earlier on Thursday, it was announced Clooney's Monuments Men co-star Bill Murray will be Letterman's last official guest on Tuesday night, as Wednesday's finale will be a tribute show. Murray was Letterman's first The Late Show guest in 1993.